We have now to inquire what means it is possible to take to ensure that the prices charged by the monopoly shall not only be the same to all, but that they shall not in themselves be so exorbitant that the monopoly will reap large profits at the public expense. How can we keep the prices charged by the monopoly from rising far above the point where they would stand if free competition were in force? Two methods are open to us. We may keep down the monopoly's rates by what we will call potential competition, or we may reduce them directly by legislative enactment.
The right of the public to take this latter course may be defended on the ground that the monopoly has voluntarily made itself a necessary public servant, and in that capacity offers to the public its goods. While it is true that the people permit the monopoly to become a necessary public servant and protect it in the contracts by which it restricts competition, it is also true that the monopoly cannot justly make merchandise of the necessities of the people. The public may allow a combination to obtain control of all the sugar refineries, for instance, and protect the combination in its formation. But suppose the owners of the combination then say: "The people are obliged to have sugar and we control the supply. We will set a high price on sugar, therefore, because we know that they will pay it rather than go without." They are then making the necessity of the public a source of gain, and it cannot be believed that this will be permanently suffered.
The serious difficulty in fixing by direct government action the prices which a monopoly of this sort shall charge, is that we cannot stop at that